The present invention disclosed herein relates to a scintillator, method for manufacturing the same and applications of scintillator.
Scintillator is a radiation sensor which converts x-ray and ionizing radiation such as gamma ray, electron beam, neutron beam to a light of visible ray wavelength region. It has been used in various areas such as medical imaging system, a radiation detector, and industrial radiation sensor. A radiation information may be obtained by measuring a light occurred by scintillation in accordance with a radiation exposure, using a suitable light receiving element such as photomultiplier tube or a photodiode. The radiation information may be used to obtain a radiation image through a series of processes.
Since NaI:Tl material was discovered in 1948 by Hofstadter, various types of scintillator has been developed to the present along the development of radio therapeutics, nuclear physics, and high-energy physics. Beginning with NaI:Tl, scintillators such as alkali halide scintillators like CsI, NaI, CsI:Tl, BGO(Bi4Ge3O12), PbWO4, LSO(Lu2SiO5:Ce) scintillators have been studied. However, a halide scintillator of CsI and NaI series has relatively low detection efficiency to the x-ray and gamma ray since atomic number of Cs, Na, I is low as 55, 11, 53, respectively.
BGO and PbWO4 scintillators have relatively low light yield (8,200 ph/MeV, BGO)(200 ph/MeV, PbWO4) than the light yield (65,000 ph/MeV, CsI:Tl)(38,000 ph/MeV, NaI:Tl) of halide series scintillator. Lu-based oxide scintillator is high cost material, has a higher melting temperature of 2,050° C., and has a crystal structure difficult to be grown in a single crystal. Also, it has a high background because of a total of 34 natural radioactive isotopes besides 176Lu (half-life: 3.78×1010 year, the natural abundance: 2.59%) exists in Lu.